The latest DLC for Battlefield 4 known as Naval Strike finally released early last week for PlayStation 4, PlayStation 3, and Xbox 360, with a release for Xbox One late last week. The PC version was delayed until April at the time, but Premium members are actually able to get it as of right now.
The PC version of the DLC was delayed because DICE was concerned “that the combination of the pack and planned PC updates would increase performance issues on mid-range to high-end PCs”. However, it appears that situation must have been figured out quicker than expected as it is now available for premium members here on the last day of March. Non-premium members will still have to wait for an unannounced date, but it should come pretty soon based on how fast it was released for premium members.